# -*- coding: UTF-8 -*-


class Human:
    def speak(self):
        pass

    def walk(self):
        pass

class people (Human):
    def speak(self,num):
        print(num)

    def walk(self,op):
        print(op)


def tu():
    a=people()   #实例化
    a.walk("an")

if __name__ == '__main__':
    tu()